The present invention relates to a method, jig, and apparatus for machining rod lenses.
In the prior art, a method for manufacturing a rod lens is described in, for example, Japanese Examined Patent Publication No. 7-89161. Referring to FIG. 3, the manufacturing method is performed to manufacture a rod lens 11 having parallel end surfaces 63, 20a and an inclined surface 20b, which is inclined relative to the end surfaces 63, 20a by angle xcex8. The prior art manufacturing method will now be discussed with reference to FIGS. 1 and 2.
Referring to FIG. 1A, a plurality of mother rod lenses 11A are held in a frame 12, which includes two glass plates 13. The two sides of the frame 12 are each fixed to a frame spacer 14. This forms a lens assembly sheet block 15. In this state, the mother rod lenses 11A are arranged so that their axes are aligned along a straight line 10. The lens assembly sheet block 15 is then cut into lens assembly sheets 18, each having a desired thickness L. The cut surfaces of each lens assembly sheet 18 are then polished to form parallel polished surfaces 16, 17 (refer to FIG. 1B).
Referring to FIG. 2A, machining sheets 61, 62, which are glass plates or the like, are fixed to the polished surfaces 16, 17 with an adhesive. Then, the machining sheet 61 is polished to form a polished surface 61a, which is inclined relative to the polished surface 16 of the lens assembly sheet 18 by angle xcex8 (FIG. 2B). Subsequently, the machining sheet 62 is polished parallel to the polished surface 61a to form the inclined surface 20b on each rod lens 11 (FIG. 2C). The machining sheets 61, 62 are then removed from the lens assembly sheet 18. The remaining surface 20a of each rod lens 11 adjacent to the inclined surface 20b is then machined and mirror finished so that it has a predetermined length A. Finally, the rod lenses 11 are removed from the frame 12. Each rod lens 11 is shaped as shown in FIG. 3.
However, when performing the above process, the adhering of the machining sheets 61, 62 to the lens assembly sheet 18 and the polishing of the sheets 61, 62 consume time. Thus, mass-production is difficult and manufacturing costs are high. Further, since the machining sheets 61, 62 are fixed to the lens assembly sheet 18 with an adhesive, the thickness of the resulting adhesive layer is not uniform. This leads to another shortcoming in which the angle xcex8 of the inclined surfaces 20b and the length A of the remaining surfaces 20a are not constant.
It is an object of the present invention to provide a method, jig, and apparatus for machining rod lenses that has satisfactory machining accuracy and enables mass-production.
To achieve the above object, the present invention provides a method for machining rod lenses. The method includes preparing a plurality of lens assembly sheets, each holding at least a row of rod lenses. The plurality of lens assembly sheets are arranged on a plurality of holding surfaces defined on a jig. The plurality of holding surfaces are inclined relative to a reference surface of the jig by a predetermined angle. The method also includes clamping each of the lens assembly sheet with a clamp to hold the lens assembly sheet so that optical axes of the rod lenses are inclined relative to a direction perpendicular to the reference surface by the predetermined angle, grinding the plurality of lens assembly sheets, and polishing the plurality of lens assembly sheets.
A further perspective of the present invention is a method for arranging rod lenses to grind and polish the rod lenses. The method includes preparing a plurality of lens assembly sheets, each holding at least a row of rod lenses. The plurality of lens assembly sheets are arranged on a plurality of holding surfaces defined on a jig. The plurality of holding surfaces are inclined relative to a reference surface of the jig by a predetermined angle. The method also includes clamping each of the lens assembly sheet with a clamp to hold the lens assembly sheet so that optical axes of the rod lenses are inclined relative to a direction perpendicular to the reference surface by the predetermined angle.
A further perspective of the present invention is a machining jig used to perform at least one of grinding a rod lens and polishing a rod lens. The rod lens is fixed in a lens assembly sheet. The jig includes a reference surface, and a support arranged on the reference surface and having a holding surface on which the lens assembly sheet is held. The holding surface is inclined relative to the reference surface by a predetermined angle.
A further perspective of the present invention is an apparatus for machining a rod lens fixed in a lens assembly sheet. The apparatus includes a machining jig used to perform at least one of grinding the rod lens and polishing the rod lens. The jig includes a reference surface and a support arranged on the reference surface and having a holding surface for holding the lens assembly sheet. The holding surface is inclined relative to the reference surface by a predetermined angle. The apparatus also includes an index table on which the machining jig is arranged.
A further perspective of the present invention is an apparatus for machining a rod lens fixed in a lens assembly sheet. The apparatus includes a machining jig used to perform at least one of grinding the rod lens and polishing the rod lens. The jig includes a reference surface and a support arranged on the reference surface and having a holding surface for holding the lens assembly sheet. The holding surface is inclined relative to the reference surface by a predetermined angle. The apparatus also includes a table on which the machining jig is arranged.
Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.